Power transmission unit



Fl 9, 1954 .1. P. BUTTERFIELD ET AL 2,668,460

yPWER TRANSMISSION UNIT Filed Mal-cn 2, 1951 Mii//f /l/WMQ HW PatentedFeb. 9, 1954 POWER TRANSMISSION UNIT "Jfolin P. Butterfield, GrossePointe Woods, and Henry W. Gilfillan, Detroit, Mich., assignors -toChrysler Corporation corporation of'Delaware Highland Park, Mich., a

.ApplicationMarch 2, 1951, ySerial No. 213,522

6"Clams. v y'1 This inventionflrelatesto. power transmission ritsandparticular-ly topowertransmission units 'adaptedfor useV asr'versing'drivel gearing in marine drive .train installations.

"It is a-primaryobjec'to'f this 'invention to pro- 'vide a `compact'power transmission gear box `adapted for useasa reduction and reversegear unit in a marine .drive train installation wherein the 'forward andreversedrives are controlled by electrically operated `means V'that kmaybe easily and economically located at any -point adjacent to orrein'otelroin thea gear box. Reverse and reduction gearing .of th'etypeherein disclosed has been conventionally operated by mechanical linkages"or byhyd'ralic'ally -operated mechanisms and each of "these types ofcontrols has several Yrather obvious disadvantages IMechanical linkagesdevelop wear and-free..play that often ren- -der.. the con-trolVmechanisms difficult-to operate.

`In addition mechanical controls are expensive and ftheyare alsodiiiicltlto 'installat control stations remote'fromthe transmissionunit. Hydraulic controls necessitate=-pressure 'fluid pumps and pressurelfluid conduits-that vare expensive. In

(addition theiilid conduits that mustbe run to H.the various controlstations throughout the ship provide a constant source of possiblefailure which iailurenotlonly renders the control system inoperativeAbut 'further has the danger of distribu-ting. the pressiiri'ze'd control'uid to various 1ocalities Vofl the 'ship where it might ignite iires ordamage 'property` stored 4aboard the ,'ship. With the/electricallyoperated control-.system herein Idisclosed conventional weatherproofedwiring may -be easily andk economically run from the transmission gearbox to any number of control stations throughout vthe 'ship and l'theoperation o'fthegear box control 'doesinot require the shifting ofmechanical linkages noi` fthe transfer of pressurized "fluid betweenvarious locations about the ship.

-,-sociate a mechanically` operable clutch device with ltheelectrically*` controlled power transmisvsion unit' Wherebyjpo'sitivedrive` transmitting connections 'are always.. available to connect thedriving and driven memberslof the power trans- 'inission .unitin theevent. of'failure of the electrieauy 'operated 1power transmission.Control lsysltern.

It is still another object of this 'invention-to provide a'simplied'improved reversinggear box with novel control means therefor.,u

It is still another objectfcf this `ninve'riti'onfto provide a powertransmission unit Ahaving gearing connectible between the'driving fanddriven shafts thereof. by two Vtypes of 'connectiongnamely anelectromagnetically operated friction-drive transmitting connection anda-positively'f engageable mechanical drive transmitting j'connetion.

Other objects and advantages offthisfinvention will become readilyvapparentfrom areadin'g-of the attached description-"of thek'inventionand a consideration of kthe related drawings `irihereiri:

Fig.. 1 is a Vsectional elevational view-ofthe power transmission unitembodying 'theseinfventions; y Y

Fig. 2 is a sectional elevational view-taken'alng the line 2--2 of Fig.1 the vieivbeing toa `reduced scale; I

Fig. 3 is 'a fragmentary sectional'elcvatinal View of analternateform'o'f driven 'shaitend connection; and

Fig. 4 is a schematic vieW'of the'eletrioal con- V.trol circuit from thepower transmission unit-dis- .shaft l l is shown piloted' within 'therear end portion of driving "shaft I!! by means ofa bearing assembly It.Encir'cling and extending between the adjacent ends 'of the shafts "Ill,'Il 'is adifferential gear unit l5. Differential Agear `i`1iiit"-l`5comprises a pair of axiallyspaced'apartsideigear elements It and 'l1respectively. Side 'geareela ment It is drivingly connected-"tothe'driving shaft lo by means of the splined connection '18. Side gearelement "l1 is connected to' the fi'rven shaft ii by means of thesplined connection 19. Enoircling the axially spacedsidejgears T6; lafi'd journalled thereon by means of l'the' bearingsZ is thedifferential carrier case 2t. Carrier case 2l is of a two-piece or splitcase construction wherein the two parts of fthefcasing'are heldinassembled position by'mea'ns of afplurality of bolt'and nut connections22.

Mounted within thercarr'ier case *2|v 'and' journalled on theforvvardend portion' ofthe-driven shaft il` is 'a pini'onigear supportiner'nber'dill.

Pinion gear support member 24 comprises a hub portion with a pluralityof radially extending spoke elements 25 projecting from the hub thatjournal the several differential pinion gears 26. In the constructionherein disclosed the support member 24 has four spoke elements 25 whichspoke elements are arranged at right angles to y one another (see Fig.2). vThe outer ends of the ential pinion gear elements 26 are formed ascombination bearing and gear elements wherein the outer race of thebearing element provides the pinion gear element that meshingly engageswith and extends between the axially spaced apart side gear elements I6,|1. It is realized that other types of differential pinion gears thanthose herein disclosed may be utilized in a differential transmissiongearing of the type herein `disclosed without altering applicantsinvention in any way but this type of pinion gearing has been found tobe quite satisfactory.

Encircling the differential carrier case 2| and arranged on oppositesides of the armature member 3D are a pair of electromagnetic coilelements 32 and 34 respectively. The coil elements 32 and 34 aresubstantially thick rings that in- -cludelmeans around their outerperipheral surfaces whereby the rings may be supported in predeterminedpositions within the housing i2. Coil ring 32 is xedly connected to thehousing i2 by means of the peripheral flange formation 35 that isconnected to housing I2 by the bolt and nut connectors 36. Flangeformation 35 is pierced by an opening 31 that receives a conductorelement 38 adapted to connect the coil 39 of ringr 32 to a suitableelectrical source.

The coil ring 34 has a sten formation 4| in its outer peripheral surfacethat receives a ring element 42; Ring element 42 is connected to thecoil ring 34 by means of screw connectors such as the connector 43. Ring42 is supported by and connected to a spider element 45 by means of boltconnections 46. Hub element 41 of the spider element 45 is drivinglyconnected tothe driven shaft |I by means of the solined connection 48.ASpider element 45 has suitably mountedtherein conductor elements 49that are adapted to transmit electrical energy from a suitable supplysource to the coil element of the .coil ring 34. As spider element 45 isrotatable a suitable slip ring connection 52 is provided between thefixed electrical contacts 53 and the rotatable conductors 49. The leads55 for the fixed contacts 53 may be supported in the walls of atransmission case breather pipe 54 or anchored in position withinhousing I2 in any other suitable manner.

Encircling the carrier case 2| of the differential gear unit andarranged on the outer sides of the coil elements 32 and 34 are a pair ofarmature members 6| and 62 respectively. The armature members 6I and 62are drivingly connected to the carrier case 2| by means of drive pinconnections such as the pins 63. .Armature e16- ments 6| and 62 areaxially shiftable along the carrier case 2| due to the looseness of thepin connections 63. Resilient means, not shown, may be provided tonormally space each of the armature members 30, 6|, 62 from theadjacently positioned electromagnetic coil rings 32 and 34. Suchresilient means are not absolutelynecessary and can be omitted ifdesired.

Operation of the power transmission unit hereinabove described is asfollows:

If the driven shaft is to be driven forwardly, that is in the samedirection as the driving shaft .|0, then the electromagnetic clutchelement 34 is energized and the electromagnetic brake element 32 isdeenergized whereby the armature members 36 and 62 will be drawn intofrictional engagement with the opposite side surfaces of the coil member34 such that the carrier case 2| and the driven shaft will be drivinglylocked together. With the carrier case 2| xed to the driven shaft thedifferential gearing |6, 26, I1 is locked in a fixed condition and driveis transmitted directly from the driving shaft lll to the driven shaftat a l to 1 ratio. If reverse drive is to be transmitted through thegear box, that is drive of the driven shaft in a direction opposite tothat of the drive shaft l0, then the electromagnetic brake 32 isenergized and the electromagnetic clutch element 34 deenergized wherebythe armature elements 6| and 30 are drawn into frictional engagementwith the opposite side surfaces of the fixed brake element 32.Engagement of the armature member 30 with the fixed brake element 32anchors the differential carrier case 2| against rotation. With thecarrier case 2| anchored to the housing |2 by brake 32 then rotation ofthe driving side gear I6 will cause the pinion gear elements 26 torotate in such a manner that the driven side gear l1 will be rotated ina direction opposite to that of the driven side gear I6. As side gears|6, I1 are fixedly connected to their respective shafts I0, it isobvious that the driven shaft will be driven in a direction opposite tothat of the driving shaft I0.

Input to the driving shaft I6 may be directly from an engine crankshaftor through gearing (not shown) that is meshingly engaged with the piniongear element 1| that is keyed to the driving shaft l0 as at 12. Theoutput from driven shaft may be transmitted to a nal drive element (notshown) through reduction gearing (not shown) that is meshingly engagedwith the drive pinion 13 that is splined to the rear end portion ofdriven shaft by the connection 14. If direct drive from the driven shaftil to a final drive element such as a prop shaft or the like is desired,then, a hanged connection such as that shown at 15 in Fig. 3 may beutilized to connect driven shaft to the final drive member to be driventhereby.

Marine reversing gearing of the general type herein disclosed'has beenplagued by a phenomena that is very objectionable and often causesserious trouble. This phenomenav results from the fact that when thepower transmission gearing is established in a neutral or no-drivecondition, there is a broken driving train between the driving anddriven shafts that will permit the driven shaft |I to rotate freely ineither direction. Accordingly, if the transmission is moved from aforward or reverse drive transmitting condition to the neutral positionthe passage of water through the associated propeller shaft, as the boatglides through the water,

assente@ i's'fsuicientto'"-keepthe"propeller *shaft rotatingandlfiequently the rotatingv propeller" will ful lines; ls'h" nets`land"otherV gear L"located beneath the vessel. An even moreseriousconsequencev ofthefact that ftheres a'brokendrive connection'bfetweentheedriving' and drivend shaftswlien thetransmission gearing'is-'arranged inra neutral ornodrivecondition: results `fromthe'fact'that friction within ther-gearunit I 5 may* be suflii'ent t'`cause the diffrentiallgearing' to transmitsome drivel between` thedriving and driven'- 'shaftsfI-I 05 I I feverr though the #clutch rand fbrake f devices itil; 3li'offthe transmission` gearingr arein" a'fdeenil ergi'zed''conditio'n.- As' aresult'ifftlie transrni sion is linneutral 'and the-engine is idling orf-ibe-Lt y device ll'isreleasedandthereafter'the contact ingr" raced towarm it'fup,thereisffrdangerI that ther-propeller shaft 1will` -rotate and fthe.shipfmayfmove P either forwardly iforin areverse= direction" unlssit'issuitably anchore'dffattlieftime; This undesired"l movement l off thevessel due".l toi` :the friction fof? the differential i gearingItransmittingdrivelcanf'frequentlyfLcause:damage fto. the'fvessel;and/.or ito fishing-f gear y'or 'structureslocated z ad-iY jacent? tolory beneath'. the vessel "at the. time/:of: the f. unintended'.movementt..

The r. invention.'` herein .iv disclosed; provides ameans:..for1:eliminatingzany: undesired: movement of: ftheidrivenfsha-ft-'I I. Whenever-the transmission: gearingis lin anoedrivelor neutralzconditioni Un` intended rotationof...the'drivensha1t I I is-pre-v ventedl'by means'of therbralqeymechanisrnv thatisradapted-to be frictlonally engagedfwith asidesurface ofV the spider `element -fl5-wheneverfthe transmission.' isconditioned1 for.` neutral VVor.; Ano:. driver Brakewmechanismcomprises:an elec-- tromagneticxcoil. ring BI- having .as-ide. surface82f-.--that-is normallyfmaintainedin light-ffiictional-`engagementfwith.the surface portion'a ofithe spider element 455C'oilfring--S-I issupportedfrom@` theftransmissionrhousing: IfbyYrneansfofafplu.m rality of stud bolts B3 (only:,one.:sl'lown)'. BoltsS31-.have their lthreaded ends fconnectedeinto the housing -I 2 fso. asto lockthe 4bearingelements I 3 imposition in the housing Ill; Thevheadzends-Tof.- therbolts yStare provided: withi axially:extendingstud+likef-formatonsl35 that seat inbOreSeMr-ini thecoil ring81| :so as::to:anchorf-thefcoil-ringifh againstrotation.l Stud. portions85roffbolts-z83i mountcompression :springs .37E thatnormallyvurgefthefcoil ring 81| into light1engagement with-the surface'portion iwofthe-'spider 45. f Conductors'- 88 that connettfth'e coil 89 of t coil4`ring' Ir :tot-a.: suitable-source of electrical: energy-may.` befhouseidi Within vthe breather pipe' 5Min; the isarmermanner:aspreviouslyf'described' with'fregardrto :fthe coni-1` ductors 1 vforthe slipi'ring: device `52;

The fcontrol f circuitA for fthe fseveralf electromage; neticallyoperatedA clutchand brakezelements-asesociated .with'this atransmission? vis 'schermatically? shownnFig. .4.x In ltliisfcircut"diagram' the :loatl-z teryx.r or.L generator or .tother;:source`ofrelectrical. energy-: 9 Iuis :grounded iat; r9 zrand'iszconnected"*byf conductor-9 3 VA.to afm'ovablefcontact .ethattisffcai riedbysthetransmission: controlile'ver. 953:'. trolzleveri95'may-thelocatedfatffany :point either, near :to or-V remotev fromfth'eftransmissionztgearf box'fembodyng this. invention; Movablelfcontact- 94of the :control leverf951is. adaptediftofb'e selec-Ytivelyiengagedf'with.the ccntactsila., @Sblor Ste:

When :control lever 95 sisiplacedin theneutr'al 'ou' drive ipositiondesignatedby ithe 1etter;2' l Fig; 4 then contact Bkl'iengages'contactf 35e l the colli 89 ilof- .thef brake device A21-'8B isenergized so'as toan'chor the-spider member-45 andiassoeiev 9`4'isengaged'witl the contact. 96e to'activate. the clutch. 34 of.' the.power transmissionpunit.. for the transmissionv of 'forward 'dri-ve.Conversely, if reverse drive is' desired 'the control lever 95 is movedfrom...the neutral position' N` towardsV the right or. L in`.ai.clockwise .manner .towards they reverse drive.position.indicatedby.ther-letter R in Fig. 4 and vthe.movable.contactSllwillrst become disengaged irommthecontact.ellaand thereafterengagedwith'the contactr Seb to activate .theelectromagnetichrakelS'Zl'. With thetransmission conetrollmechanism.hereinldisclosed it is .thought to'be ObiLiOusth'atthebrake '.devicet!! .will be activated wheneverthe transmission. is.moved .from a drive transmittingscondition or R into a. So-calledneutral -orv-,no-drive condition Llccordinglyu the-re...ivill. neverbearotation. of .the drivene shaft I I= except at .atim e..,when the.transmission hasv actuallybeenset for. aldrive transmitting condition.

The -powentransmission -.un-itv hereinabove described is arranged tobe...co-ntrolledbv electrically` controlled 4powertransmissionnnitfrombeing .in-

i* operative when there might be a failurein. the

power.. supplyv sour-ce, v.this rtransmission. includes means.wherebvan' auxiliary;y mechanically operated, .clutchsdevice -I Ullmay..be manually operated to.v positively'. connect the driving and'. drivenshafts-III, ..I I.V .irrespective .of the condition of the electrical..controls for.. the. power. transmission uniti; 'I'.le manuallyoperablemechanical. clutch Ifcomprises atothed sleevelll! .splined vto the.

drivingshaftsl 0 atl'l 02"'and shiftable axially along the .drivingshaftll. The teeth |03 of sleeve IBI are .adapted tbe movedintoand outof engagementwith`t'eeth` yI IJ`4 frmed -aroundthe .periphery of .jan.openirigintheside wallof. the. carrier case. 2"I`Lf1 When the.teethl'of 'sleeve IBI are engaged with.. the .teeth'l I 0`4'of 'carriercase 2 I then drivingshaft IUandLcarrier. case2I are locked to.-getherdn. suoli'v a mannerthatthe dilferential gearing. I 6', f2 61" ITjibecomes .a unitary structure andftransmits diieetdrivefrom .thedriveshaft ldtdthedriven shaft""l I.. The clutchidevioe IM isitle mechanicalequivalentof the electromagn'etically operated "clutch 34 fand thusthistransmission includes .twomeans whereby; direct drive may' be.transmittedbetween"the shafts IQ, II, l' one means' beingitlemechanical.clutch IB@ and the other :"meang" the f electromagn'etically`controlled/clutched?" A'etuatiorr'.oftliertoothed clutch sleeveV I 0 Iis controlledby themovementof the clutchv operat- -ing.".lever`*l06i"Ilevenltispivoted 'at I0? to an ear.` I 08 carriedibyrthe transmissionhousing I2.

groove|Illiformedrintlretsleve I0! such that sleeve" I0 Imay'rotaterelative to the lever end f I 09151 'I'he-'epivoted'endiof'lever' I 66 'h'as f a .portion is held in the position shown in Fig. 1.VSet screw H2 is maintained in this position by means of the anchor wireH3 that is connected between an anchor device I i4 and the head of theset screw H2. Resilient means such as the spring H5 is compressedbetween the housing wall |08 and the clutch operating lever I such thaton release of the set screw H2 the spring H5 will swing the operatinglever IDE counterclockwise about its pivot point |01 and thereby movethe toothed sleeve I0! into engagement with the teeth IM of the carriercase 2l. Due to the availability of the positive clutch mechanism l, italways is possible to transmit drive between the shafts I0 and I2 eventhough the electrical system for controlling the several electromagneticclutches and brakes 32, 34, 8B might be inoperative. Furthermore, as theclutch device it can be utilized to positively connect the driving anddriven shafts i0, H it is possible to start the L engine unit associatedwith this power transmission device by means of pulling the vesselthrough the water and causing the propeller to drive the engine and tothus cause ring of the engine even though the electrical system might bedead. The incorporation of a positive safety clutch such as a clutch |00in an electrically operated power transmission unit of the type hereindescribed is considered to be a very definite improvement in mechanismsof the type herein described. It will be noted that the positive clutchdevice H may be simultaneously engaged during engagement of theelectromagnetically operated clutch 34 to prevent slip of the clutch 34,or it may be separately operated when the clutch 34 is inoperative.

We claim:

1. In a transmission comprising a housing journalling a pair of axiallyaligned driving and driven shafts, a differential gear set connectedbetween said shafts comprising a carrier case extending between androtatably mounted on said shafts, a side gear drivingly mounted on eachof said driving and driven shafts, said side gears being arranged inspaced apart, opposed relationship within said carrier case, piniongearing journalled in said carrier case and arranged to extend betweenand meshingly engage said side gears, a ring-like armature encirclingand drivingly connected to and axially shiftably mounted on said carriercase, an annular electromagnetic brake element fixed to said housing andencircling said case and arranged adjacent a side surface of saidarmature, energization of said brake element being effective to anchorsaid armature member and said carrier case to said housing to providemeans for the drive of said driven shaft in a direction opposite to thatof said driving shaft, an annular electromagnetic clutch element carriedby said driven shaft and encircling said case and arranged adjacent.another side surface of said armature, energization of said clutchelement being effective to drivingly connect said carrier case and saiddriven shaft to provide means for the drive of said driven shaft in thesame direction as said driving shaft, said aforementioned armature andassociated clutch and brake elements being arranged concentrically aboutsaid carrier case, a second electromagnetic brake element fixed to saidhousing having portions arranged adjacent to and adapted to be engagedwith portions of said driven shaft on energization of said second brakeelement to anchor said driven shaft against rotation in eitherdirection, and a control circuit for said electromagnetic clutch andbrake elements tionship within said carrier case, pinion gearingjournalled in said carrier case and arranged to extend between andmeshingly engage said side gears, a ring-like armature assemblydrivingly connected to and encircling said case, said arma-V tureassembly being shiftable axially on said carrier case, an annularelectromagnetic brake element fixed to said housing and encircling saidcase and arranged adjacent a side surface of said armature assembly,energization of said brake element being effective to anchor saidarmature member and said carrier case to said housing to provide meansfor the drive of said driven shaft in a direction opposite to that ofsaid driving shaft, an annular electromagnetic clutch element carried bysaid driven shaft and encircling said case and arranged adjacent anotherside surface of said armature assembly, energization of said clutchelement being effective to drivingly connect said carrier case and saiddriven shaft to provide means for the drive of said driven shaft in thesame direction as said driving shaft,v and a manually operable positiveclutch mounted on one of said shafts and engageable between said carriercase and one of said driving or driven shafts to supply a mechanicalconnection between the driving and driven shafts providing a secondmeans for effecting rotation of said shafts in the saine direction.

3. In a transmission comprising a housing journalling a pair of axiallyaligned driving and driven shafts, a differential gear set connectedbetween said shafts comprising a carrier case extending between androtatably mounted on said shafts, a side gear drivingly mounted on eachof said driving and driven shafts, said side gears being arranged inspaced apart, opposed relationship within said carrier case, piniongearing journalled in said carrier case and arranged to extend betweenand meshingly engage said side gears, a ring-like armature drivinglyconnected to and shiftably mounted on said carrier case, an annularelectromagnetic brake element fixed to said housing and encircling saidcase and arranged adjacent a side surface of said armature, energizationof said brake element being effective to anchor said armature member andsaid carrier case to said housing to provide means for the drive of saiddriven shaft in a direction opposite to that of said driving shaft, anannular electromagnetic clutch element carried by said driven shaft andencircling said case and arranged adjacent another side surface of saidarmature, energization of said clutch element being eective to drivinglyconnect said carrier case and said driven shaft to provide means for thedrive of said driven shaft in the same direction as said driving shaft,brake means mounted on said housing and arranged to be engaged with saiddriven shaft to anchor said driven shaft against rotation in eitherdirection, and a manually operable clutch carried by one of said shaftsand engageable between said carrier case and one of said driving ordriven shafts to supply a mechanical connection between the driving anddriven shafts providing a second means for effecting rotation of saidshafts in the same direction.

4. In a transmission comprising a housing journalling a pair of axiallyaligned driving and driven shafts, differential gearing arranged betweensaid shafts comprising side gears drivingly connected to each of saidshafts and arranged in opposed, axially spaced, relationship, a carriercase enclosing and journalled on said side gears, a pinion gear supportmounted in said carrier case having radially extending spoke elementspiercing said carrier case, pinion gears journalled on said spokeelements within said carrier case and arranged to extend between andmeshingly engage said side gears, a first ringlike armature unitencircling said carrier case and drivingly connected to said pinion gearsupport and shiftable axially of the case, a pair of electromagneticcoil rings encircling said carrier case and arranged adjacent oppositesides of said first armature unit, one of said coil rings being fixed tosaid housing and the other of said coil rings being xed to one of saidshafts, a pair of second ring-like armature units encircling saidcarrier case and axially shiftable relative thereto, said pair of secondarmature units being drivingly connected to said carrier case andarranged such that each of said second armature units has anelectromagnetic coil ring interposed between it and the first armatureunit, said armature units and said coil rings being arrangedconcentrically about the gearing of the differential gear set andelectrical circuit control means for said coil rings to provide forselective energization and deenergization of said coil rings.

5. In a transmission comprising a housing journalling a pair of axiallyaligned driving and driven shafts, differential gearing arranged betweensaid shafts comprising side gears drivingly connected to each of saidshafts and arranged in opposed, axially spaced, relationship, a carriercase enclosing and journalled on said side gears, a pinion gear supportmounted in said carrier case having radially extending spoke elementspiercing said carrier case, pinion gears journalled on said spokeelements within said carrier case and arranged to extend between andmeshingly engage said side gears, a ring-like armature unit encirclingsaid carrier case and drivingly connected to said pinion gear supportand shiftable axially of the case, a pair of electromagnetic coil ringsencircling said carrier case and arranged adjacent opposite sides ofsaid armature unit, one of said coil rings being fixed to said housingand the other of said coil rings being fixed to one of said shafts,brake means carried by said housing adapted to be applied to said drivenshaft to anchor said driven shaft against rotation, a manually operableclutch member carried by said driving shaft and connectible between saiddriving shaft and said carrier case, and electrical circuit controlmeans for said coil rings to provide for selective energization anddeenergization of said coil rings.

6. In a transmission comprising a housing journalling a pair of axiallyaligned driving and driven shafts, differential gearing arranged betweensaid shafts comprising side gears drivingly connected to each of saidshafts and arranged in opposed, axially spaced, relationship, a carriercase enclosing and journalled on said side gears, a pinion gear supportmounted in said carrier case having radially extending spoke elementspiercing said carrier case, pinion gears journalled on said spokeelements within said carrier case and arranged to extend between andmeshingly engage said side gears, a ring-like armature unit encirclingsaid carrier case and drivingly connected to said pinion gear supportand said case and shiftable axially of the case, a pair ofelectromagnetic coil rings encircling said carrier case and arrangedadjacent opposite sides of said armature unit, one of said coil ringsbeing fixed to said housing and the other of said coil rings being fixedto one of said shafts, brake means carried by said housing adapted to beapplied to said driven shaft to anchor said driven shaft againstrotation, a manually operable clutch connectible between said drivingshaft and said carrier case, said manually operable clutch comprising atoothed sleeve drivingly connected to said driving shaft and axiallyshiftable relative thereto, a toothed portion carried by said carriercase adapted to be drivingly engaged with said toothed sleeve, a shiftlever for said toothed sleeve movably mounted on said housing, resilientmeans normally urging said toothed sleeve into engagement with saidtoothed portion of the carrier case and adjustable means mounted on saidhousing engageable with said shift lever to oppose said resilient meansand hold said sleeve out of engagement with the case, and electricalcircuit control means for said coil rings to provide for selectiveenergization and deenergization of said coil rings.

JOI-IN P. BUTTERFIELD. HENRY W. GIIElLLAN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,293,190 Pollard Feb. 4, 1919 1,476,458 Murray Dec. 4, 19231,932,983 Morgan Oct. 31, 1933 2,118,464 Ftzhugh May 24, 1938 2,236,631Thomas et al Apr. 1, 1941 2,296,520 Griswold Sept. 22, 1942 2,317,135Crittenden et al. Apr. 20, 1943 2,547,038 Parrish Apr. 3, 1951 2,587,015Walter Feb. 26, 1952 2,613,773 Gilflllan Oct. 14, 1952 FOREIGN PATENTSNumber Country Date 30,791 Norway June 7, 1920 136,468 Great BritainDec. 18, 1919 433,627 Great Britain Aug. 19, 1935

